Applicability of the Crow-AMSAA Model

The Duane and Crow-AMSAA models are the most frequently used reliability growth models. Their relation comes from the fact that both make use of the underlying observed linear relationship between the logarithm of cumulative MTBF and the cumulative test time. However, the Duane model does not provide a capability to test whether the change in MTBF observed over time is significantly different from what might be seen due to random error between phases. The Crow-AMSAA model allows for such assessments. Also, the Crow-AMSAA allows for development of hypothesis testing procedures to determine growth presence in the data ( indicates that there is growth in MTBF, indicates a constant MTBF and indicates a decreasing MTBF). Additionally, the Crow-AMSAA model views the process of reliability growth as probabilistic, while the Duane model views the process as deterministic.